Field of the Invention
The invention relates to a method for removing solidified ink or varnish from a surface of an object in which a cleaning agent is applied to the ink on the surface.
Known methods for removing layers of solidified ink or varnish rely on the use of a solvent, generally subjecting the surface to stress. In order to effectively remove layers of ink, in most cases, the surface is additionally subjected to rubbing or scrubbing. That may damage the surface or result in undesired surface changes. Moreover, that process only removes the layer of ink bit by bit. In addition, small bits of ink may be created that in turn stick to the surface and need to be removed in a time-consuming second cleaning step. A process of removing layers of ink of that kind has turned out to be difficult, in particular for strongly or greatly curved surfaces.
European Patent EP 1 875 490 B1, corresponding to U.S. Pat. No. 8,752,228, discloses a device for cleaning circuit substrates. In one embodiment of that invention, the circuit substrate is passed through a gap between two rollers, each of which presses a cleaning web formed of a carrier web and a cleaning tissue onto the surface of the circuit substrate. Initially, a cleaning liquid is applied either to the surface of the circuit substrate or to the cleaning tissue. The rollers guide the cleaning tissue over the surface of the circuit substrate and the cleaning tissue removes contamination in the form of foreign particles from the surface, absorbs them, and carries them away. In a further embodiment, the cleaning tissue carries an adhesive material. The adhesive material and the material of the carrier web are selected to ensure that adhesion between the carrier web and the adhesive material is greater than adhesion between the adhesive material and the surface of the circuit substrate. During the cleaning process, there is no relative movement between the circuit substrate and the cleaning web. The rollers successively press a new section of the cleaning web onto parts of the surface of the circuit substrate until the entire surface has been treated. In that process, the foreign particles stick to the adhesive surface of the cleaning web.
Japanese Patent Application JP 2001 353 856 A discloses an adhesive sheet for removing solvent-containing substances from surfaces. The adhesive sheet is formed of a base material and an adhesive layer, which is applied to at least one surface of the base material. The adhesive sheet is immersed in the solvent contained in the substance to be removed for three minutes and the adhesive layer absorbs at least 20 g/m2 of the solvent.